ARE the restless and vengeful spirits of dead dogs and slaughtered Native Americans to blame for a sensational murder and a mysterious death on Long Island’s East End?

That’s the eerie theory of Sam Wagner, who’s researching a book about flamboyant Hamptons antique dealer Barton Kaplan – found dead in his swimming pool four years ago, naked except for the jungle-red nail polish on his toes.

Wagner was Kaplan’s boyfriend. He has discovered that the land where both Kaplan and financier Ted Ammon – who was savagely beaten to death by his estranged wife Generosa’s lover, Danny Pelosi – built their estates was a battleground where thousands of Montauk Indians were killed in a bloody war with the Narragansett tribe in 1653.

“Now it’s 350 years later, and the land has still got its mysterious and horrible deaths,” Wagner tells Page Six. He says Barton, who had a 2.7-acre East Hampton estate on Middle Lane, bought the property in 1998 from Peter Marcy “on one condition – that he would not disturb the graves of three dogs Marcy had buried in the back yard. When Barton had his pool put in, he forgot to tell the builders, and the graves and markers were destroyed.” Four years later, Barton died in the very same pool of alcohol poisoning, possibly a suicide.

Wagner also believes that Generosa’s intense hatred of Ted may have stirred up ghosts on their property, also on Middle Lane. “Ted Ammon was cursed out by Generosa, who felt that she was going to be cheated out of millions in their divorce settlement. Was her intense hatred of him enough to bring about his demise from whatever spirits have died in that area, which could have possessed Danny Pelosi into committing the murder?” he says.

He says that last year, Barton’s father rented the house to a family of CVS drugstore heirs for $550,000 for the summer, but had to give them an extra month for free. “There were too many problems: doors slamming in the night, water running in bathrooms at will and lights going on. It’s now for sale,” says Wagner, whose tome will be titled, “The House That Barton Built.”